Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors
Because of the high viscosity of severe chain entanglements, a time-consuming process of aligning microstructural orientation in high molecular-weight (Mw) block copolymer photonic crystal films imposed limitations on efficient mass production. In this study, the effective alignment of the block cop...
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| Format: | Article |
| Language: | English |
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Elsevier
2024-03-01
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| Series: | Giant |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666542523000875 |
| _version_ | 1827311129007751168 |
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| author | Yuan Xiang Wei-Tsung Chuang Yeo-Wan Chiang |
| author_facet | Yuan Xiang Wei-Tsung Chuang Yeo-Wan Chiang |
| author_sort | Yuan Xiang |
| collection | DOAJ |
| description | Because of the high viscosity of severe chain entanglements, a time-consuming process of aligning microstructural orientation in high molecular-weight (Mw) block copolymer photonic crystal films imposed limitations on efficient mass production. In this study, the effective alignment of the block copolymer microstructures in the film state can be carried out within approximately a few minutes. This achievement was realized through the synergistic localized compatibility of dry brush and shear stress during the spin-casting process. The orientation and orderliness of the microphase-separated lamellar structure in as-spun poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) films can be meticulously controlled by introducing blends with PS homopolymer (hPS) of varying Mws (Mw,hPS) and cholesteric liquid crystal mesogen (Chol). Within the ternary blended films of hPS/PS-b-P4VP(Chol), the wet-brush miscibility by blending low-Mw hPS with a small molecular weight ratio (α) of Mw,hPS to Mw,bPS (Mw of the PS block chain) of α <1 results in the formation of disoriented lamellar structures, whereas dry-brush localization by introducing high-Mw hPS with α∼0.9 yields highly parallel-aligned lamellar structures to the substrate after spin casting, even with a massive quantity of additive hPS (∼59 wt%). The dry-brush compatibility can be demonstrated by morphological observation in the ternary blended film after extraction of the hPS. As a result, without any further efforts, such as additional solvent or thermal annealing treatments, the as-spun ternary blended film can exhibit visible structural colorations with controlled wavelengths by alternating the quantity of hPS. This provides an accessible solution for rapidly producing flexible photonic crystals featuring tunable photonic band gaps. |
| first_indexed | 2024-03-08T15:31:41Z |
| format | Article |
| id | doaj.art-7aa05b2fa61f482a91600581b98c011a |
| institution | Directory Open Access Journal |
| issn | 2666-5425 |
| language | English |
| last_indexed | 2024-04-24T20:12:05Z |
| publishDate | 2024-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Giant |
| spelling | doaj.art-7aa05b2fa61f482a91600581b98c011a2024-03-23T06:26:07ZengElsevierGiant2666-54252024-03-0117100225Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectorsYuan Xiang0Wei-Tsung Chuang1Yeo-Wan Chiang2Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 80424, TaiwanNational Synchrotron Radiation Research Center, Hsinchu 30076, TaiwanDepartment of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan; Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Corresponding author at: Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.Because of the high viscosity of severe chain entanglements, a time-consuming process of aligning microstructural orientation in high molecular-weight (Mw) block copolymer photonic crystal films imposed limitations on efficient mass production. In this study, the effective alignment of the block copolymer microstructures in the film state can be carried out within approximately a few minutes. This achievement was realized through the synergistic localized compatibility of dry brush and shear stress during the spin-casting process. The orientation and orderliness of the microphase-separated lamellar structure in as-spun poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) films can be meticulously controlled by introducing blends with PS homopolymer (hPS) of varying Mws (Mw,hPS) and cholesteric liquid crystal mesogen (Chol). Within the ternary blended films of hPS/PS-b-P4VP(Chol), the wet-brush miscibility by blending low-Mw hPS with a small molecular weight ratio (α) of Mw,hPS to Mw,bPS (Mw of the PS block chain) of α <1 results in the formation of disoriented lamellar structures, whereas dry-brush localization by introducing high-Mw hPS with α∼0.9 yields highly parallel-aligned lamellar structures to the substrate after spin casting, even with a massive quantity of additive hPS (∼59 wt%). The dry-brush compatibility can be demonstrated by morphological observation in the ternary blended film after extraction of the hPS. As a result, without any further efforts, such as additional solvent or thermal annealing treatments, the as-spun ternary blended film can exhibit visible structural colorations with controlled wavelengths by alternating the quantity of hPS. This provides an accessible solution for rapidly producing flexible photonic crystals featuring tunable photonic band gaps.http://www.sciencedirect.com/science/article/pii/S2666542523000875Block copolymerDry brushSpin castingPhotonic crystalLiquid crystal |
| spellingShingle | Yuan Xiang Wei-Tsung Chuang Yeo-Wan Chiang Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors Giant Block copolymer Dry brush Spin casting Photonic crystal Liquid crystal |
| title | Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| title_full | Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| title_fullStr | Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| title_full_unstemmed | Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| title_short | Synergistic effects of dry-brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| title_sort | synergistic effects of dry brush compatibility and shear stress on rapid alignment of lamellar microstructures for block copolymer reflectors |
| topic | Block copolymer Dry brush Spin casting Photonic crystal Liquid crystal |
| url | http://www.sciencedirect.com/science/article/pii/S2666542523000875 |
| work_keys_str_mv | AT yuanxiang synergisticeffectsofdrybrushcompatibilityandshearstressonrapidalignmentoflamellarmicrostructuresforblockcopolymerreflectors AT weitsungchuang synergisticeffectsofdrybrushcompatibilityandshearstressonrapidalignmentoflamellarmicrostructuresforblockcopolymerreflectors AT yeowanchiang synergisticeffectsofdrybrushcompatibilityandshearstressonrapidalignmentoflamellarmicrostructuresforblockcopolymerreflectors |